In article ,
Adam H. Kerman wrote:
Stephen Sprunk wrote:

There is no way for the terminal to know whether the Visa/MC/etc. number
presented is a credit, debit or charge card. A card processor _may_ be
able to deduce it from other information, but only the issuing bank
knows for sure.

I have no idea how you come up with this stuff, but the type of card,
not to mention who issued it, is built into the number range itself.

Adam 'knows not that of which he speaks'.

Steven is correct.

_Some_ issuers used different blocks of initial digits on the card to
designate what type of card. Some DID NOT.

I wrote software for credit-card processing and related accounting functions
at a PPOE. t was _impossible_ to accurately generate -- at the time of the
transaction -- the 'costs' of processing certain 'card' transactions -- the
biggest 'offender' on this was VISA -- because one could _not_ determine
'debit' vs 'credit' AT THE TIME OF THE TRANSACTION, and 'debit' cards were
charged _MUCH_HIGHER_ transaction rates than 'credit' cards. I had
extended arguments with the support people at VISA itself (not the card
processor I used, not the issuing bank, _VISA_ -- who set the rates).
Some of the more polite language included things like 'pig in a poke'.

There was eventually a _lawsuit_ (not my employer) over this issue, the
card issuers lost, an the 'cost differential' was eliminated.

However, the inability differentiate 'credit' vs 'debit' in a non-trivial
percentage of cases _remains_.